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Js/Ruby: Share IncompleteHostnameRegExp.ql

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This commit is contained in:
Arthur Baars
2022-03-02 18:28:47 +01:00
parent 097c661362
commit 98f56f4d60
8 changed files with 200 additions and 188 deletions
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2
ruby/ql/lib/codeql/ruby/security/performance/RegExpTreeView.qll
View File

@@ -398,6 +398,8 @@ class RegExpAlt extends RegExpTerm, TRegExpAlt {
override string getAPrimaryQlClass() { result = "RegExpAlt" }
}
class RegExpCharEscape = RegExpEscape;
class RegExpEscape extends RegExpNormalChar {
RegExpEscape() { re.escapedCharacter(start, end) }

98
ruby/ql/src/queries/security/cwe-020/HostnameRegexpShared.qll
View File

@@ -3,8 +3,7 @@
* that match URLs and hostname patterns.
*/
private import codeql.ruby.security.performance.RegExpTreeView
private import codeql.ruby.DataFlow
private import HostnameRegexpSpecific
/**
* Holds if the given constant is unlikely to occur in the origin part of a URL.
@@ -20,7 +19,7 @@ predicate isConstantInvalidInsideOrigin(RegExpConstant term) {
/** Holds if `term` is a dot constant of form `\.` or `[.]`. */
predicate isDotConstant(RegExpTerm term) {
term.(RegExpEscape).getValue() = "."
term.(RegExpCharEscape).getValue() = "."
or
exists(RegExpCharacterClass cls |
term = cls and
@@ -108,3 +107,96 @@ predicate alwaysMatchesHostnameAlt(RegExpAlt alt, int i) {
alwaysMatchesHostnameAlt(alt, i - 1) and
alwaysMatchesHostname(alt.getChild(i))
}
/**
* Holds if `term` occurs inside a quantifier or alternative (and thus
* can not be expected to correspond to a unique match), or as part of
* a lookaround assertion (which are rarely used for capture groups).
*/
predicate isInsideChoiceOrSubPattern(RegExpTerm term) {
exists(RegExpParent parent | parent = term.getParent() |
parent instanceof RegExpAlt
or
parent instanceof RegExpQuantifier
or
parent instanceof RegExpSubPattern
or
isInsideChoiceOrSubPattern(parent)
)
}
/**
* Holds if `group` is likely to be used as a capture group.
*/
predicate isLikelyCaptureGroup(RegExpGroup group) {
group.isCapture() and
not isInsideChoiceOrSubPattern(group)
}
/**
* Holds if `seq` contains two consecutive dots `..` or escaped dots.
*
* At least one of these dots is not intended to be a subdomain separator,
* so we avoid flagging the pattern in this case.
*/
predicate hasConsecutiveDots(RegExpSequence seq) {
exists(int i |
isDotLike(seq.getChild(i)) and
isDotLike(seq.getChild(i + 1))
)
}
predicate isIncompleteHostNameRegExpPattern(RegExpTerm regexp, RegExpSequence seq, string msg) {
seq = regexp.getAChild*() and
exists(RegExpDot unescapedDot, int i, string hostname |
hasTopLevelDomainEnding(seq, i) and
not isConstantInvalidInsideOrigin(seq.getChild([0 .. i - 1]).getAChild*()) and
not isLikelyCaptureGroup(seq.getChild([i .. seq.getNumChild() - 1]).getAChild*()) and
unescapedDot = seq.getChild([0 .. i - 1]).getAChild*() and
unescapedDot != seq.getChild(i - 1) and // Should not be the '.' immediately before the TLD
not hasConsecutiveDots(unescapedDot.getParent()) and
hostname =
seq.getChild(i - 2).getRawValue() + seq.getChild(i - 1).getRawValue() +
seq.getChild(i).getRawValue()
|
if unescapedDot.getParent() instanceof RegExpQuantifier
then
// `.*\.example.com` can match `evil.com/?x=.example.com`
//
// This problem only occurs when the pattern is applied against a full URL, not just a hostname/origin.
// We therefore check if the pattern includes a suffix after the TLD, such as `.*\.example.com/`.
// Note that a post-anchored pattern (`.*\.example.com$`) will usually fail to match a full URL,
// and patterns with neither a suffix nor an anchor fall under the purview of MissingRegExpAnchor.
seq.getChild(0) instanceof RegExpCaret and
not seq.getAChild() instanceof RegExpDollar and
seq.getChild([i .. i + 1]).(RegExpConstant).getValue().regexpMatch(".*[/?#].*") and
msg =
"has an unrestricted wildcard '" + unescapedDot.getParent().(RegExpQuantifier).getRawValue()
+ "' which may cause '" + hostname +
"' to be matched anywhere in the URL, outside the hostname."
else
msg =
"has an unescaped '.' before '" + hostname +
"', so it might match more hosts than expected."
)
}
predicate incompleteHostnameRegExp(
RegExpSequence hostSequence, string message, DataFlow::Node aux, string label
) {
exists(RegExpPatternSource re, RegExpTerm regexp, string msg, string kind |
regexp = re.getRegExpTerm() and
isIncompleteHostNameRegExpPattern(regexp, hostSequence, msg) and
(
if re.getAParse() != re
then (
kind = "string, which is used as a regular expression $@," and
aux = re.getAParse()
) else (
kind = "regular expression" and aux = re
)
)
|
message = "This " + kind + " " + msg and label = "here"
)
}

2
ruby/ql/src/queries/security/cwe-020/HostnameRegexpSpecific.qll Normal file
View File

@@ -0,0 +1,2 @@
import codeql.ruby.security.performance.RegExpTreeView
import codeql.ruby.DataFlow

93
ruby/ql/src/queries/security/cwe-020/IncompleteHostnameRegExp.ql
View File

@@ -12,96 +12,5 @@
*/
import HostnameRegexpShared
import codeql.ruby.security.performance.RegExpTreeView
import codeql.ruby.DataFlow
import codeql.ruby.AST as AST
/**
* Holds if `term` occurs inside a quantifier or alternative (and thus
* can not be expected to correspond to a unique match), or as part of
* a lookaround assertion (which are rarely used for capture groups).
*/
predicate isInsideChoiceOrSubPattern(RegExpTerm term) {
exists(RegExpParent parent | parent = term.getParent() |
parent instanceof RegExpAlt
or
parent instanceof RegExpQuantifier
or
parent instanceof RegExpSubPattern
or
isInsideChoiceOrSubPattern(parent)
)
}
/**
* Holds if `group` is likely to be used as a capture group.
*/
predicate isLikelyCaptureGroup(RegExpGroup group) {
group.isCapture() and
not isInsideChoiceOrSubPattern(group)
}
/**
* Holds if `seq` contains two consecutive dots `..` or escaped dots.
*
* At least one of these dots is not intended to be a subdomain separator,
* so we avoid flagging the pattern in this case.
*/
predicate hasConsecutiveDots(RegExpSequence seq) {
exists(int i |
isDotLike(seq.getChild(i)) and
isDotLike(seq.getChild(i + 1))
)
}
predicate isIncompleteHostNameRegExpPattern(RegExpTerm regexp, RegExpSequence seq, string msg) {
seq = regexp.getAChild*() and
exists(RegExpDot unescapedDot, int i, string hostname |
hasTopLevelDomainEnding(seq, i) and
not isConstantInvalidInsideOrigin(seq.getChild([0 .. i - 1]).getAChild*()) and
not isLikelyCaptureGroup(seq.getChild([i .. seq.getNumChild() - 1]).getAChild*()) and
unescapedDot = seq.getChild([0 .. i - 1]).getAChild*() and
unescapedDot != seq.getChild(i - 1) and // Should not be the '.' immediately before the TLD
not hasConsecutiveDots(unescapedDot.getParent()) and
hostname =
seq.getChild(i - 2).getRawValue() + seq.getChild(i - 1).getRawValue() +
seq.getChild(i).getRawValue()
|
if unescapedDot.getParent() instanceof RegExpQuantifier
then
// `.*\.example.com` can match `evil.com/?x=.example.com`
//
// This problem only occurs when the pattern is applied against a full URL, not just a hostname/origin.
// We therefore check if the pattern includes a suffix after the TLD, such as `.*\.example.com/`.
// Note that a post-anchored pattern (`.*\.example.com$`) will usually fail to match a full URL,
// and patterns with neither a suffix nor an anchor fall under the purview of MissingRegExpAnchor.
seq.getChild(0) instanceof RegExpCaret and
not seq.getAChild() instanceof RegExpDollar and
seq.getChild([i .. i + 1]).(RegExpConstant).getValue().regexpMatch(".*[/?#].*") and
msg =
"has an unrestricted wildcard '" + unescapedDot.getParent().(RegExpQuantifier).getRawValue()
+ "' which may cause '" + hostname +
"' to be matched anywhere in the URL, outside the hostname."
else
msg =
"has an unescaped '.' before '" + hostname +
"', so it might match more hosts than expected."
)
}
from
RegExpPatternSource re, RegExpTerm regexp, RegExpSequence hostSequence, string msg, string kind,
DataFlow::Node aux
where
regexp = re.getRegExpTerm() and
isIncompleteHostNameRegExpPattern(regexp, hostSequence, msg) and
(
if re.getAParse() != re
then (
kind = "string, which is used as a regular expression $@," and
aux = re.getAParse()
) else (
kind = "regular expression" and aux = re
)
)
select hostSequence, "This " + kind + " " + msg, aux, "here"
query predicate problems = incompleteHostnameRegExp/4;